By Councilor Dan McIlroy
Sedona AZ (November 22, 2011) – The City of Sedona operates and maintains a waste water treatment system. This system pumps waste water nine miles underground by sixteen pumping stations located throughout the city from the Chapel area to the plant southwest of town on SR 89A. The residents and commercial businesses produce between one million and one million, two hundred thousand gallons of waste water per day. In order to dispose of treated waste water, known as effluent, the city uses a series of sprayers. The effluent is sprayed on fields. Through transpiration and evaporation, the water goes into the air.
The city is supplementing its present waste water disposal system with the following considerations:
The city is constructing a series of wetland ponds on 27 acres of land at the waste water treatment plant as part of a test pilot project for enhancing effluent management. These wetlands will be composed of six esthetically and gravitationally designed ponds that will move treated waste water from higher elevation ponds to lower elevation ponds and then be pumped back to the upper pond to create adequate circulation in the wetlands. The wetlands are expected to be completed in the spring of 2012. These wetlands ponds will provide a habitat for birds and wildlife along with a scenic area for walking and jogging. It is hoped that local tour groups will find these wetland ponds an attractive stopping point on their tours.
Another management approach being evaluated is injecting A plus treated water into the ground water. Before this can be done, the present B plus waste water must be upgraded to A Plus quality. This process requires the installation of a new ultraviolet system that will increase the wastewater plant’s ability to remove bacteria from the water. This system is expected to be installed by spring of 2012. The system may also have some impact on pharmaceuticals, lotions, solvents and pesticides. The wetlands and the ultraviolet treatment system will cost approximately two million dollars. This money has already been set aside for this purpose. Injection testing will follow after the wetlands and ultraviolet systems are operational.
In an effort to reduce the cost of electricity, the city is considering installing solar panels on approximately ten acres of the waste water plant acreage. The city recently released a request for proposal (RFP) to potential solar providers. As of September 28th, eighteen vendors have responded. It will take city staff several months to review and evaluate these proposals. When the selection is made, the chosen vendor will install the solar panels at no cost to the city, sell electricity to us for less than we expect to be paying Arizona Public Service (APS), and maintain the panels for twenty years. At the end of twenty years, the ownership of the panels will pass to the city at reduced or no cost.
The incentive for the solar vendor is a subsidy from the federal government along with one from APS. APS offers this subsidy because it is under a mandate from the Arizona Corporation Commission to generate fifteen percent of its power by alternative sources such as solar, wind, geothermal and nuclear by 2025.
By spraying, utilizing the wetlands, injection, and the savings afforded by the solar panels, the city will experience a cost effective and environmentally friendly way of disposing of excess A plus treated waste water.
The opinions expressed in this article are those of Councilor Dan McIlroy and not those of the City of Sedona or the Sedona City Council.